From German Patent 20 07 441 the generation of an ammonia synthesis gas is known, where by gasifying hydrocarbons a raw gas is generated, which is desulfurized, converted, liberated from CO2 and finally subjected to washing with liquid nitrogen for removing residual impurities. In EP patent 0 307 983 a similar process is described, wherein prior to the synthesis of ammonia converted synthesis gas is subjected to washing with liquid nitrogen. Details of the catalytic production of ammonia can be found in Ullmann's Encyclopedia of Industrial Chemistry, 5th edition, vol. A2, pp. 143-215; the production of urea is described there in vol. A 27, pp. 333-350.
Subject-matter of EP 0 931 762 A is a process of producing gas rich in hydrogen from dimethyl ether and/or methanol by adiabatic catalytic steam reforming in an oxygen-containing atmosphere. The heat necessary for the endothermal steam reforming reactions is generated by oxidizing part of the hydrogen obtained from the feed mixture treated by steam reforming. The product gas is supplied to an ammonia synthesis, where it is possible to remove the carbon dioxide from the product gas and use the same for the synthesis of urea. This process is not much suited for generating hydrogen as starting product for the large-scale production of ammonia, as temperatures of the gas mixture generated by steam reforming, which are decisive for the size of the yield of hydrogen, cannot be controlled with sufficient accuracy.
It is the object underlying the invention to treat a vaporous feed mixture of methanol and steam by means of endothermal gasification such that a gas mixture with a predominant content of hydrogen as compared to carbon dioxide can be produced, in order to be able to produce ammonia on an industrial scale.